Many machines include an enclosed cab to protect the operator and provide a more comfortable environment in which to operate the machine. Such cabs may include a heating, ventilating, and air conditioning (HVAC) system to control the temperature and/or humidity inside the cab. Such HVAC systems may both draw air into the cab from exterior to the cab, and recirculate air within the cab for additional adjustment of the temperature or humidity of the air inside the cab. In order to remove particles from the air entering the cab, a filter may be provided, through which air drawn into the cab by the HVAC system may be filtered. In addition, particles may be removed from air recirculated inside the cab by another filter.
However, having separate filter assemblies and associated ducting for air drawn into the cab and air recirculated within the cab may occupy more space than desired, potentially resulting in insufficient space for other desired features inside the cab. In addition, it may be desirable to reduce the number of parts in the machine to reduce manufacturing and maintenance costs, including costs associated with machine down-time for servicing multiple filters.
An example of an HVAC system that includes a filter for filtering fresh air from outside a vehicle as well as air recirculated inside the vehicle is described in U.S. Patent Application Publication No. US 2012/0214394 A1 to Kanemaru et al. (“the '394 publication”). According to the '394 publication, a housing defines an exterior fresh air intake aperture and an interior recirculation air intake aperture. A suction passage is in communication with both the exterior and interior air intake apertures. A first door is operably associated with the exterior air intake aperture for selectively opening and closing the exterior air intake aperture. A second door operably associated with the interior air intake aperture selectively opens and closes the interior air intake aperture. The first and second doors are movable independent of each other, and a partition for at least partially dividing the suction passage is located upstream of a filter in the suction passage. In a mixture mode, the first door is configured to control ram pressure as vehicle speed increases to maintain a predetermined airflow ratio between fresh air flowing into the housing via the exterior air intake aperture and recirculation air flowing into the housing via the interior air intake aperture.
Although the HVAC system disclosed in the '394 publication includes a partition upstream of a filter, the system is complex and relies on a pair of movable doors and the partition to direct air to a planar filter. Thus, the system described in the '394 publication may occupy more space than desired and requires a relatively complex arrangement including a large number of parts resulting in elevated manufacturing and maintenance costs.
The filter element and filter assembly disclosed herein may be directed to mitigating or overcoming one or more of the possible drawbacks set forth above.